Alan_Weiss <aweiss@mathworks.com> wrote in message <kg5piv$7ss$1@newscl01ah.mathworks.com>...> On 2/21/2013 6:16 AM, Pascal Schulthess wrote:> > Hi everyone,> >> > I'm working quite a long time with lsqnonlin and comparable functions > > but now I'm wondering if there's a difference between the following > > two expressions of the cost function:> >> > First:> > f = [0,1];> > function error = objFcn(p, x, y)> > fit = zeros(size(ydata));> > for i = 1:size(ydata, 1)> > fit(i,:)= p(1)*x + f(i)*p(2);> > end> > error = fit-y;> > end> >> > And, secondly:> > function error = objFcn(p, x, y)> > fit = zeros(size(ydata));> > fit(1,:)= p(1)*x;> > fit(2,:)= p(1)*x + p(2);> > error = fit-y;> > end> >> > I would really appreciate any help and possible explanations.> >> > Thanks a lot,> >> > Pascal> > Well, I'm not sure what is the error or warning you are seeing, or what > is the problem you are experiencing.> > If I have to guess, it seems to me that the "fit" matrix has a different > size in the second formulation than in the first. But I really don't > know, because you haven't told us the size of your matrices.> > Alan Weiss> MATLAB mathematical toolbox documentation

Hi,there's no error message. It's more a general question.Ok, so, in the first case, p(2) is basically present in both equations (fit(1,:) and fit(2,:)) except that it is multiplied by a factor (0). My question now is if p(2) is also considered by the fitting routine in fit(1,:) or (as it should be) only in fit(2,:)?I hope I made myself clear.Thanks,Pascal